The present invention relates specifically to a bulk semiconducting material that consists of a uniform distribution of nanoscale polycrystalline grains wherein the diameter of the polycrystalline grains is limited to nanometer physical dimensions such that the nanoscale texture of the semiconducting material induces quantum-size effects within the polycrystalline grains that endow the bulk semiconductor with electrical or optical properties (herein referred to as “general dielectric properties”) of a three-dimensional (3D) electron gas. An additional specific embodiment of the invention relates to methods and processes that diffuse electrically conducting or electrical insulating materials into the grain boundaries of the nanoscale polycrystalline grains.
The present invention relates generally to the monolithic assembly of an active electronic, photonic, or opto-electronic device that comprises a layer of semiconductor material having thickness greater than 50 nm which exhibits the general dielectric properties of a 3D electron gas onto a semiconductor chip carrier that is used to electrically interconnect various additional semiconductor die into a more sophisticated microelectronic system. Such various active electronic or opto-electronic devices may include, but are not limited to, high power density/high-speed power management circuits, stable clock generators, electrical signal modulators, optical sensors, optical power generators, optical signal generators and/or modulators or thermoelectric systems,
1. Description of the Prior Art
T. J. Phillips et al. (U.S. Pat. No. 7,173,292), (hereinafter referred to as Phillips '292), teaches that runaway currents (avalanche breakdown) caused by impact ionization in modulation-doped field effect (MODFET) or high electron mobility (HEMT) transistors applied to narrow band gap semiconductor materials is mitigated or substantially eliminated by forming a quantum well field effect transistor (QWFET). The quantum well FET consists of thin multi-layered structures comprising one or more wide band gap semiconductors. (See FIGS. 1&2). FIG. 1 depicts a vertical cross section of a QWFET 1 that comprises a quantum well region 2 embedded between two wide band gap semiconductor layers 3,4. The quantum well region 2 consists of a plurality of differing semiconductor layers 5,6,7. The central layer 6 forms a primary conduction channel that is bounded by semiconductor materials 5,7 forming secondary conduction channels having semiconductor band gaps 21,22 greater than the band gap 23 of semiconductor material that is used in the layer forming the primary conduction channel 6, but less than the band gaps 24,25 of the wide band gap semiconductor layers 3,4. FIG. 2 shows the representative energy band gap diagram 20 for the layered semiconductor structure depicted in FIG. 1 viewed from cross-sectional perspective defined by X-X′.
The field effect device is created by inserting the quantum well region 2 between two conductive doped source 8 and drain 9 regions. An electrical bias applied to the gate electrode 10 is then used to modulate current supplied to the source electrode 11 when it is collected by the drain electrode 12. The high charged carrier mobilities available in QWFET devices enable high switching speeds reported in the range between 250 GHz to 1 THz, and thus have value in high switching speed systems or millimeter-wave communications systems.
In a QWFET device, the central layer 6 must be sufficiently thin (20-50 nm) to form a 2-D electron gas through quantization effects in the quantum well contained in the primary conduction channel. The quantization effects are generated by the nanometer scale thickness of the central layer 6 and the height of the band edges 26,27 created by contacting to the semiconductor layers 5,7 that form the quantum well 28. These quantization effects create the discrete energy levels 29,30 of the high electron mobility 2-electron gas. The semiconductor layers 5,7 provide higher ionization thresholds that prevent currents flowing in the primary conduction channel in the central layer 6 from undergoing avalanche breakdown through impact ionization processes. Examples of low band gap semiconductor materials used in the primary channels are indium antimonide (InSb), indium arsenide (InAs), indium arsenic antimonide (InAs(1-y)Sby), indium gallium antimonide (In(1-x)GaxSb), and/or indium gallium arsenide (In(1-x)GaxAs).
2. Definition of Terms
The term “active component” is herein understood to refer to its conventional definition as an element of an electrical circuit that that does require electrical power to operate and is capable of producing power gain.
The term “alkali metal” is herein understood to refer to its conventional definition meaning the group of metallic elements in column IA of the periodic table, consisting of lithium, sodium, potassium, rubidium, cesium, and francium.
The term “alkaline earth metal” is herein understood to refer to its conventional definition meaning the group of metallic elements found in column IIA of the periodic table, consisting of magnesium, calcium, strontium, barium, and radium.
The term “amorphous material” is herein understood to mean a material that does not comprise a periodic lattice of atomic elements, or lacks mid-range (over distances of 10's of nanometers) to long-range crystalline order (over distances of 100's of nanometers).
The term “chemical complexity”, “compositional complexity”, “chemically complex”, or “compositionally complex” are herein understood to refer to a material, such as a metal or superalloy, compound semiconductor, or ceramic that consists of three (3) or more elements from the periodic table.
The term “chip carrier” is herein understood to refer to an interconnect structure built into a semiconductor substrate that contains wiring elements and embedded active components that route electrical signals between one or more integrated circuits mounted on chip carrier's surface and a larger electrical system that they may be connected to.
The term “electron gas” is herein understood to refer to its generally accepted definition as a collection of electrons (or holes) that are free to move within a modified solid via tunneling processes and have higher mobilities than they would normally have in a similar unmodified solid, wherein quantization effects generated by the solid's modification (typically nanoscale layering) induce a quantum energy well that govern and define the transport properties of the electrons (holes) and minimize interactions between the electron (holes) located within the quantum energy well.
The term “FET” is herein understood to refer to its generally accepted definition of a field effect transistor wherein a voltage applied to an insulated gate electrode induces an electrical field through insulator that is used to modulate a current between a source electrode and a drain electrode.
The term “halogen” is herein understood to refer to its conventional definition meaning the nonmetallic elements contained in column VIIA of the periodic table consisting of fluorine, chlorine, bromine, iodine, and astatine.
The term “halogenated” is herein understood to refer to its conventional definition meaning a molecule or substance that has been treated or combined with a halogen.
The term “integrated circuit” is herein understood to mean a semiconductor chip into which a large, very large, or ultra-large number of transistor elements have been embedded.
The term “LCD” is herein understood to mean a method that uses liquid precursor solutions to fabricate materials of arbitrary compositional or chemical complexity as an amorphous laminate or free-standing body or as a crystalline laminate or free-standing body that has atomic-scale chemical uniformity and a microstructure that is controllable down to nanoscale dimensions.
The term “liquid precursor solution” is herein understood to mean a solution of hydrocarbon molecules that also contains soluble metalorganic compounds that may or may not be organic acid salts of the hydrocarbon molecules into which they are dissolved.
The term “microstructure” is herein understood to define the elemental composition and physical size of crystalline grains forming a material substance.
The term “mismatched materials” is herein understood to define two materials that have dissimilar crystalline lattice structure, or lattice constants that differ by 5% or more, and/or thermal coefficients of expansion that differ by 10% or more.
The term “nanoscale” is herein understood to define physical dimensions measured in lengths ranging from 1 nanometer (nm) to 100's of nanometers (nm).
The term “opto-electronic device” is herein understood to refer to any device that uses an electrical signal to modulate an optical signal having energetic characteristics defined by the optical, infrared (near, mid or far), millimeter wave, sub-millimeter wave, or ultraviolet (near or far) regions of the electromagnetic spectrum, or visa-versa.
The term “passive component” is herein understood to refer to its conventional definition as an element of an electrical circuit that that does not require electrical power to operate and is capable of altering an electrical signal's amplitude and/or phase or being used as an energy storage device.
The term “photonic device” is herein understood to refer to a device that uses a signal having energetic characteristics defined by the optical, infrared (near, mid, or far), millimeter wave, sub-millimeter wave, or ultraviolet (near or far) electromagnetic spectrum to modulate one or more additional signal having energetic characteristics defined by the optical, infrared (near, mid, or far), millimeter wave, sub-millimeter wave or ultraviolet (near or far) regions of the electromagnetic spectrum.
The term “power FET” is herein understood to refer to the generally accepted definition for a large signal vertically configured MOSFET and covers multi-channel (MUCHFET), V-groove MOSFET, truncated V-groove MOSFET, double-diffusion DMOSFET, modulation-doped transistors (MODFET), heterojunction transistors (HETFET), and insulated-gate bipolar transistors (IGBT).
The term “quantum dot” is herein understood to apply to its conventional meaning of a material domain that is small enough to induce quantum-size effects that exhibit the electronic, optical, or opto-electronic characteristics of an electron gas.
The term “standard operating temperatures” is herein understood to mean the range of temperatures between −40° C. and +125° C.
The terms “tight tolerance” or “critical tolerance” are herein understood to mean a performance value, such as a capacitance, inductance, or resistance that varies less than ±1% over standard operating temperatures.
The term “II-VI compound semiconductor” is herein understood to refer to its conventional meaning describing a compound semiconductor comprising at least one element from column IIB of the periodic table consisting of: zinc (Zn), cadmium (Cd), or mercury (Hg); and, at least one element from column VI of the periodic table consisting of oxygen (O), sulfur (S), selenium (Se), or tellurium (Te).
The term “III-V compound semiconductor” is herein understood to refer to its conventional meaning describing a compound semiconductor comprising at least one semi-metallic element from column III of the periodic table consisting of: boron (B), aluminum (Al), gallium (Ga), and indium (In); and, at least one gaseous or semi-metallic element from the column V of the periodic table consisting of: nitrogen (N), phosphorous (P), arsenic (As), antimony (Sb), or bismuth (Bi).
The term “IV-IV compound semiconductor” is herein understood to refer to its conventional meaning describing a compound semiconductor comprising a plurality of elements from column IV of the periodic table consisting of: carbon (C), silicon (Si), germanium (Ge), tin (Sn), or lead (Pb).
The term “IV-VI compound semiconductor” is herein understood to refer to its conventional meaning describing a compound semiconductor comprising at least one element from column IV of the periodic table consisting of: carbon (C), silicon (Si), germanium (Ge), tin (Sn), or lead (Pb); and, at least one element from column VI of the periodic table consisting of: sulfur (S), selenium (Se), or tellurium (Te).